Precision approach path indicator: Difference between revisions

Revision as of 01:57, 17 February 2005

Revision as of 17:47, 19 February 2005

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The '''Precision Approach Path Indicator (PAPI)''' is a [[light]] system positioned beside the runway that consists of two or four boxes of lights that provide a visual indication of an airplane's position on the [[glidepath]] for the associated [[runway]]. The [[FAA]] standard for the PAPI is the same as the [[ICAO]]'s standard Visual Glide Slope Indicator.

Each box of lights is equipped with an [[optics|optical]] apparatus that horizontally splits light output into two phasessegments: red (the lower segment) and white. Depending on the viewing, (and thus the descent), angle, a pilot will see either the red or the white portion.

A normal glidepath is indicated by an even split in red and white lights. If an airplane is beneath the glidepath, more red lights are visible to the pilots; if an airplane is above the glidepath, more white lights are visible.

During aircraft [[descent]], this system, along with other airport lights, may be activated by the [[pilot]] by keying the airplane [[microphone]] with the airplane's communication radio tuned to the [[CTAF]].

== Sources ==

* [http://www.faa.gov/ATPubs/AIM/Chap2/aim0201.html#2-1-2 FAA Aeronautical Information Manual: Visual Glideslope Indicators]

* [http://av-info.faa.gov/terps/Directives_files/8260.49.pdf FAA TERPS directive]